The approaches described in this section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, the approaches described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.
Distributing security credential information for use in verifying and proving the identity of a computer network device is a problem in the fields of network and information security. For example, in cryptosystems that use public key cryptography, there is a need to verify that a public key actually belongs to its purported owner, so that the public key can be trusted. One approach for establishing such trust is to use a root digital certificate to sign the key prior to distribution. For a recipient to then verify the signed key, the recipient must first receive the root certificate in some manner. Thus, examples of credentials for which distribution is commonly needed include public key-private key pairs, digital certificates such as server root certificates and public key certificates, and other material.
Certain packet-switched networks use authentication servers to authenticate clients that request access to protected resources, including end station devices such as servers and printers, and other infrastructure elements such as routers or switches. In this context, a requesting client may wish to receive a credential, such as a digital certificate, to verify an authentication server. Alternative, the client may need to receive its own certificate to use to prove its own identity to another domain. For example, a client may receive a digital certificate from an enterprise domain and then use that certificate to sign communications to other domains. As still another example, there may be a need to distribute a public/private key pair to a device that cannot otherwise perform a key exchange.
Typically, a subscriber and a peer communicate in a non-secure conversation, and the credentials are distributed manually through a separate, out-of-band process that is typically secured using encryption. However, this approach suffers from the drawbacks that a separate out-of-band process must be established and agreed upon by the peers; encryption keys must be exchanged among the peers in some manner; and the existence of a separate channel creates a new opportunity for attack or exploitation by a malicious interloper.
Thus, there is a need for a way to distribute credentials to a subscriber automatically through an in-band process. It would be particularly desirable to have a way to distribute the credentials within the context of an existing secure conversation between the subscriber and peer.
An authentication approach for network devices is described in L. Blunk et al., “PPP Extensible Authentication Protocol,” IETF Request for Comments 2284, March 1998. The “EAP” approach of RFC 2284 provides a generalized way for a first network element to authenticate the identity of a second network element.
EAP implementations have been developed for many specific contexts. For example, in the context of mobile wireless devices that use the Global System for Mobile communications (GSM), an approach for authentication and deriving session keys using the GSM Subscriber Identity Module (SIM) is described in H. Haverinen et al., “EAP SIM Authentication,” IETF Internet-Draft, February 2003. In these contexts, EAP generally results in exchanging authentication credentials, and may include a key exchange in which peers acquire keys needed to decipher packets sent under a link layer protocol, such as IEEE 802.11.
Because EAP implementations are widely used, it would be desirable to have a way to distribute security credentials within the context of an EAP authentication conversation. The credentials then could be used for protecting the identity of a subscriber, authenticating additional security services, and upgrading security credentials.